Turbochargers may be used in an engine system to increase a pressure of air supplied to the engine for combustion. In one example, the turbocharger includes a turbine coupled in an exhaust passage of the engine which at least partially drives a compressor via a shaft to increase the intake air pressure. Many turbochargers use journal bearings to support the rotating shaft. These bearings are lubricated with a pressurized oil supply that is regulated to a relatively constant pressure through the use of a control valve or an orifice. Often, the steady oil pressure is monitored by a pressure transducer and a control system to assure the machine is properly lubricated and cooled.
Over time, the shaft and/or journal bearings or related components may be subject to wear. Eventually, the journal bearings may fail, for example. Often, because of this, the life of the turbocharger is shorter than the rest of the engine. Also, due to the high level of energy stored in the turbocharger, its failure is usually catastrophic. This results in the unexpected shutdown of the engine, which can have safety and cost consequences to an operator of the system.